Diaphragm seal assemblies are widely used in fluid control valves to control the flow of a wide variety of fluids through the valve at various conditions of temperature, pressure and other conditions. Such diaphragm seal assemblies typically include an elastomeric body. A stationary peripheral portion of the elastomeric body may be secured to a housing of the fluid control valve, and a diaphragm portion of the elastomeric body may be carried by the stationary peripheral portion for movement between a closed or sealed position and an opened position.
The elastomeric body of such diaphragm seal assemblies may be exposed to relatively harsh conditions of fluid composition, fluid temperature and/or fluid pressure. The elastomeric body exposed to such conditions may be cycled between its closed and opened positions frequently, over extended periods of time. Also, the elastomeric body may be exposed to steam or other cleaning agents, during periodic cleaning or when the type of fluid flowing through the valve is changed. Still further, the elastomeric body may be exposed to variable tightening forces and to extrusion forces during installation and use.
Diaphragm seal assemblies used in fluid control valves may be considered wear items that may be serviced or replaced at periodic intervals or upon condition requirements. If the diaphragm seal assembly requires relatively more frequent service (such as tightening or replacement), this may cause relatively greater expenses to be incurred for labor, parts, and possible down time for the system in which the fluid control valve is used. Accordingly, it is desirable to provide a diaphragm seal assembly that is relatively inert with respect to the fluid flowing through the fluid control valve, that is relatively maintenance free, that does not leak either between the fluid ports of the fluid control valve or externally of the fluid control valve, that does not crack or rupture or otherwise operationally degrade over prolonged cycles and periods of time, that resists extrusion during installation and use, and that may be installed relatively quickly without retightening or other maintenance after installation.
One common type of fluid control valve in which diaphragm seal assemblies may be used is a weir fluid control valve. Weir fluid control valves typically include a valve body that includes a fluid inlet port, a fluid outlet port, and a weir interposed between the inlet and outlet ports. A diaphragm seal assembly in such valves may move toward the weir to close the fluid flow between the fluid ports and away from the weir to open the fluid flow. Diaphragm seal assemblies used in weir fluid control valves may be used in a wide variety of applications, including pharmaceutical processing applications, food and beverage processing applications, and other applications in which safety, accuracy, dependability, replacement ease, and long life are important.